Changing Blood
by Marvel-Fanatic
Summary: After getting back from being held by an unsub for three days the team starts to notice something off with Derek. Meanwhile there's something murdering people in New York and leaving them drained of blood. Will the team be able to solve the case and find out what's wrong with one of their own in time to save the latest victim Supervisory Special Agent Jennifer Jareau. [Rated T]
1. Sleepless

**Hi, new story here. I know my other one's are still incomplete but I had an idea and I needed to roll with it. It's a CM and TMI crossover. I'm a huge fan of the books and I'm already involve with the new TV show based off them. So here's my new story, Changing Blood I hope you enjoy it**

 **I have added a new character named Cassandra Rogue she's been with the team since season 4 as an additional member.**

* * *

Chapter 1. Sleepless

Derek rolled over on his bed, checking his clock the illuminate numbers mocking him showing him that it was 2:34 in the morning. He groaned, he was just getting off his medical leave from being held by an unsure for 3 days straight. The dreams were unpleasant and his new condition more like sickness was a curse. He reached out and grabbed his phone, shitting up in his sheets running a hand down his face, he opened his phone. Garcia had written an app for the teams phones that would tell each other if another member was 'online' or awake so they could talk if they needed to. He sighed in relief when he saw that Cassie was up.

 _'_ _Hey, you up for talking?'_ He texted her

 _'_ _Yeah what's up, you okay?'_ She answered within the minute

 _'_ _Just can't sleep, nerves about work tomorrow and the dreams'_ He replied getting out of bed to stretch his legs.

' _Want me to call, we can talk about it''_

 _'_ _Sure'_ Seconds later his phone began to ring, he picked it up.

"Hi" He sighed

"Hey" She said gently, "So you have trouble sleeping again?"

"Obviously, and you too it seems" Her replied padding to his kitchen to grab a drink.

"Well, insomnia is a bitch" She chuckled

"I'd guess, how many hours have you gotten this week?" He asked concerned for his team meet that had trouble getting sleep

"I'm getting an average of 2 hours a night, which is great for me. I should be back to normal sleep next week, I swear my insomnia screws with me for a week and then I can sleep normally for the next month. It's like I have two periods." She ranted.

"You should've called one of the girls to complain about that." Derek chuckled., unscrewing a bottle and chugging it down.

"What the hell are you drinking at this hour?" She asked confused.

"It's just juice" He lied, putting the container that contained a red liquid back in the fridge concealed in a cabinet.

"Okay." She chuckled. "You think we'll have a case today?"

"Knowing my luck we probably will" He laughed heading back to his bed. Savannah was working the graveyard shift at the hospital so he had the house to himself. She laughed over the phone.

"Well you should probably try to get some more sleep, I'm going to spend the rest of my night doing who knows what before making my 2 gallons of coffee for the day."

"Okay." He sighed. "Thanks for just talking to me, you're a great friend"

"Correction" She grinned down the phone, "I'm an awesome friend, now go get some sleep." She hung up on him. He sat on his bed and reflected back on the recent effects that had changed him and his life for the worse.

* * *

 _Derek groaned his eyes blinking open. He saw darkness and only darkness, the last thing he remember was getting hit in the back of the head, the team was tracking an unsub that was drawing their victims of blood, and it looked like he was going to be next. He had been pursuing a lead that lead him to a conversation with a handsome young man with dark hair and blue eyes, he seemed to be in his mid 20s. Too young to be their unsub, but age was always the hardest to profile so he wasn't surprised that their had not profiled the correct age group for this killer. He scanned his surroundings and heard some shuffling in which he guess was the far corner. He was tired to a chair in the centre of a large room, it looked like a warehouse of some sort._

 _"_ _I know you're there." He called. "We can talk this out." He had to let the unsub know he was in control, had to keep him in control so he wouldn't kill him out of rage._

 _"_ _There's no talking." the man said walking up to him. "Only feeding."_

 _"_ _Feeding?" Derek asked confused._

 _"_ _Do you not remember me turning you?" The man asked. "I made you more than human, a more powerful being that ascends human kind." He grinned. Derek was able to see that his incisors were longer than all his other teeth, they were fangs, and why could he see so well in the dark?_

 _"_ _What did you do to me?" He asked in a cautious tone._

 _"_ _Do you not remember the first time you woke up young fledgling?" He asked._

 _"_ _Excuse me I'm old-"_

 _"_ _Ahh." The man interrupted him. "You are mistaken there, I'm over 100 years old."_

 _"_ _That's not possible." Derek said gently, this man clearly had some strong delusions._

 _"_ _It quite is, remember you're supposed to be dead now" He smiled creepily at Derek._

 _"_ _Huh?" Derek asked confused._

 _"_ _Think back" The mans voice suddenly turned melodic and hypnotic. "Think back to when you first woke up my young one."_

 _Derek's mind snapped back to a few hours earlier, he had woken up in the same room he was in now except something was in his mouth, it was the unsub's arm. He pulled away and swallowed nervously, that was his mistake. He felt a coppery tasking liquid go down his throat and then he saw the mans arm, the can had a cut on his arm. The unsub made Derek drink his blood. Derek stared in horror, he had drunk someone's blood, be it killer or not he had drank blood._

 _"_ _Welcome to your new life" The man spoke raising a knife and before Derek had time to react the man had slit his throat._

 _His mind snapped to another memory that was temporarily lost from him, he remember waking up and being starving, he bit onto a bag of cool red liquid and drank it down, it was delicious and cured his hunger. After that he was knocked out again._

 _"_ _What did you do to me?" He asked the man in shock._

 _"_ _I turned you, welcome to being a child of the night. Welcome to the life of a vampire" He grinned._

 _"_ _A vampire?!"_

* * *

Derek put his face in his hands, that one fateful day had changed him forever, he was a monster, a killer, not human. He was. A vampire.

* * *

 **So that's it so far, I seem to have a thing for change poor Derek into something he''s not in the show. Oh well, as always I adore reviews they're amazing. Constructive criticism is alway welcome. As** **always, see you when I decided to actually write and upload the next chapter**


	2. First Day Back

**Second chapter. Finally I know, I just didn't know what direction I wanted to take the opening chapter of introducing the characters, but here it is.**

 **Enjoy all.**

* * *

Night passed and Derek rolled over, he checked his clock. The illuminated numbers reading 5:30am.

"Thank go-" He choked as he tried to say 'God'.

"Fuck" He cursed and threw a pencil at the wall, leaving a small dent in the drywall. He sighed and shook his head. He still wasn't used to his new body and his powers. His phone started ringing. He picked it up and seeing that it was an unknown number he picked it up and answered.

"Hello?" He asked

"Is this Derek Morgan?" A women with a thick Russian accent spoke.

"Yes" He answered hesitantly.

"Perfect" He could hear her smiling down the line.

"Are you calling me about a case?" he questioned.

"No actually, a friend of mine called. Said you may need some help. I've been informed you recently came into contact with a man with the name of Dunkan Raven." She spoke gently. Derek tensed at the name of the vampire who tortured and turned him.

"So you know?" He asked slowly.

"I do." She replied, "I am also a vampire myself, I want to help you because you never asked for this life it was forced on you."

"How do I know you're just not going to use me?" He asked cautiously.

"Unlike Dunkan I'm one of the oldest vampires and I've seen some of the worst of vampire kind. I can promise you that I will help you out. I've made it my life's mission to help out young fledgling vampires who are just turned. I don't want to force anything on you I just want to let you know I can help."

"How old are you?" He questioned and then heard her sigh

"I'm around 2,000 years old, I lost count last century."

"So you really know everything about being a vampire?" He questioned

"I do, I can council you over the phone if need be or you can come find me. I live in Toronto, Canada which is where my clan is but I am making a trip down to New York in 2 days time and I understand that you live not far from there. Am I correct?"

"You are, ah" He swallowed. "I never got your name"

"Anastasia Nightcrest" She promptly told him. "Now I understand that you have to get to work and the sun's rising I've kept you for too long, put this number in your contacts and call me if need be or if you need someone to provide you blood, whether it be human, animal, or both, whatever your preference it."

"Thank you" He smiled gently and then heard the click from the other line as Anastasia hung up.

* * *

Derek walked into the bullpen just seeing the sun coming through the small rectangular windows on the concrete walls. He saw the familiar head of red hair of his co-worker and friend Cassie, her face on her the desk and paperwork that she was most likely drooling on now as snores came from her.

"Oh Cas" He chuckled seeing her. "Baby Girl" He called Garcia over, "Go put a fresh pot on, someone looks like she'll need it" He smiled sticking a thumb over to the woman who was asleep on her desk.

"Oh the poor thing" Garcia frowned, "Is her insomnia acting up again?"

"Yeah, she called me last night when I couldn't sleep too." Derek replied

"Hey all" Spencer walked up on Morgan and Garcia, "Why're you just standing here?" He questioned.

"Your girlfriend there is sleeping on the job" Morgan pointed out Cassie to Reid who frowned. "She's not my girlfriend. We've been best friends for years, plus, she's gayer than the NBC logo." Reid's statement caused Garcia to choke on the coffee she was drinking.

"How do you know that?"

"Please" He scoffed, " We were roommates in university, you don't want to know how many girls she brought home." He smiled.

"Seeing you 2 together brings out a whole new side of you pretty boy" Morgan smiled, "I'm glad she transferred here from Tactical Forces. And aren't you 2 living together again?"

"Yeah." He nodded, "Make rent a little easier to pay plus my place is big enough we don't get in each other's way, but I'll tell you she complains about how we don't get enough guns a lot. Tactical brought out her violent and gun obsessed side." He smiled as the 3 agents laughed at that.

"I'll go get her coffee started." Garcia returned to the task at hand of waking up the young agent and headed to their mini kitchen.

"So, do you wanna wake her up…" Morgan turned to Reid.

"Hell no" He shook his head. "She will tackle you, you do it I had enough of it in university."

"Fine" He grumbled and walked over to Cassie's desk. "Cas" He said gently reaching down to shake her shoulders. "Wake up, you're at work." All he got in response was angry mumbling.

"Wake up before Hotch gets here" He advised, "we don't want the newbie in hot water with the boss." He chuckled pulling her up from her armpits. She groaned as he moved her and the sheet she had been drooling on was now sticking to her face. Reid snorted at the sighed and pulled out his phone taking a picture of it.

"Blackmail" He grinned to himself and put it back in his pocket as he walked over to the fridge and went into the freezer. He grabbed a few ice cubes from the tray and walked over to Derek who was holding Cassie who didn't want to wake up yet. He pulled her shirt back slightly and dropped the ice cubes down her back. She yelped bolting up, whirling around and glaring at Reid growling at him.

"Dude run" Morgan advised. Reid smiled innocently putting his mug down and then bolted.

"SPENCER YOU LITTLE SHIT!" Cassie screeched and the bolted after him. Morgan and Garcia cackled as the 2 agents disappeared, a ticked off Cassie on Reid's heels. Morgan smiled, messing with his friends and acting like normal helped distract him from what he was currently going though and how he'd most likely have to leave at some point when they noticed he wasn't aging anymore. He sighed turing to Garcia,

"I'm going to get started on paperwork, let me know if she hurts pretty boy." He smiled and then turned on his heel walking to his office. Once in his life glad that his office didn't have any windows.

* * *

Derek jumped as Cassie knocked at his office door.

"You okay?" She asked walking in, files in her arms, "You normally don't jump." She frowned trying to read his face.

"I'm fine Cas" He waved it off, "You done those?" He questioned eyeing the files in her arms.

"No sarcastic comment on how I was drooling on them a few hours ago?" She smiled gently trying to cover up the worry that was digging at her.

"Just tired Cas" He assured, "You should probably try and head home, see if you can get to bed. By the way don't you have meds for your insomnia?"

"Our schedule is so irregular I can't really go on meds. I'd be in a dead sleep when we're called in and I won't be able to be woken up." She shrugged. "But mine isn't that bad, I get sleep when I can. Which reminds me, you eventually get anymore sleep last night?"

"I got a bit" He smiled.

"That's good" She grinned, "And here" She handed him a tupperware "My dad's famous cookies. Welcome back, I enlisted Spencer to help and he didn't burn any this time." She grinned. Morgan laughed, "you two are great friends and bring out other sides of your personalties, also since we were talking about your not so straightness this morning, how's your girlfriend?"

"Amazing" She sighed her eyes getting a glazed lovestruck look to then.

"Good for you too." Morgan smiled and then winced as hunger and cramps hit him.

"You okay?" She frowned walking up to him. He snatched the files from her hand and then growled. "Get out!"

"Okay" She jumped at the growl and held up her hands backing out of the office and shutting the door behind her.

"Dammit" Morgan sighed and put the folders down on his desk, leaning against it. "I have to get this under control." He said out loud to himself. He looked down to see his paler than normal hands shaking as he started to crave blood. He could hear people's heartbeats at they passed his office and could smell their blood. He threw open the mini fridge he kept in his office and grabbed the small bottle of animal blood he brought to work out of it. Unscrewing the lid and taking a few gulps from it, wincing as his fangs extended and ripped into his bottom lip.

"Derek?" Garcia said knocking at his door. "Can I come in?"

"One minute!" He called quickly chugging the rest of the blood and then throwing the bottle back into the fridge sipping the excess from his mouth and making sure his fangs had retracted. He sat at his desk and then called for Garcia to come in.

"You okay Chocolate Pudding?" She asked walking in, "Cassie just told me you snapped at her."

"I'm fine" He sighed, "I didn't get much sleep last night and I've been have small flashbacks so I've been stressed. I'll find her and apologize as soon as I can."

"Good." Garcia smiled, "I don't was me best friends fighting, speaking of best friends, have you seen JJ at all today?" Morgan's browns furrowed in thought as he tried to remember if he saw the petit blond agent.

"No I haven't," He shook his head, "any chance she took the day off to spend with the boys?"

"Possibly, but I've texted her and she hasn't responded." Garcia frowned remembering the last time JJ had gone missing.

"If she doesn't respond in 3 hours you have my permission to trace her cell." He said standing up and walking around his desk to pull her into a hug. "And she's JJ, she'll be okay I'm sure she's just busy with her sons."

"Thanks Derek."

"Anytime Baby Girl."

* * *

"I'm telling you Spencer, something's off with Derek." Cassie and Spencer were back at their apartment after a slow day of paperwork. Spencer was curled up on the recliner with a book and Cassie was cleaning one of her Glocks.

"You're being paranoid, he just got back from being held hostage for three days" Spencer rolled his eyes as She interrupted his reading yet again.

"He didn't smell right." She said looking over the gun and then sliding the magazine back in.

"Smell are you serious?" He peered at her from over the top of the hard cover he was reading.

"He didn't smell mundane Spence, he doesn't smell like he used to. He smells dead." She said looking into his eyes.

"You think he was turned some how."

"How else can I explain it. Unless my scenes have stated going crazy." She said

"Scar" He sighed, "You seriously think Morgan is now a vampire?"

"Well I'm one I know a vampire when I smell one, especially fledglings."

"You're half vampire." He rolled his eyes "And fine say if Morgan is a vampire, we help him?"

"Well we don't want dead mundanes piling up in Washington with all their blood drained of them so yeah." She rolled her eyes. "I'll call mom."

"Good call getting Anastasia in on this, you're not that experience being a vampire Scar."

"I am 99 years old shut the hell up mr. I'm an oh so power half warlock and I know everything." She glared at him.

"Well I do since I'm older than you." He smirked

"I can tell, is that a little grey in your hair." She retorted with her own smirk. He rolled his eyes. "Bite me" She shot at her going back to his book.

"That can be arranged" She smirked at his her fangs flashing in the light as she got up and went to the fridge to pour herself a glass of blood.

* * *

Morgan peaked out the window of the bullpen and sighed in relief once he saw that the sun had gone down. He grabbed his bag that he had pack up a half hour before and headed for the parking garage. Driving home after a long first day back full of stress and hunger pains. He chugged down some blood once he got home grimacing at the taste, he laid back on his couch flipping through the late night shows trying to find something to fall asleep too when his phone buzzed with a text. He looked at the notification seeing it didn't come from any of his known contacts. Opening the phone he scrolled to find the conversation and opened it reading through the text.

 _Thought you'd hear the last of your creator. You thought wrong little fledgling, Im going to make as many as I can, and no one can stop me._

Morgan suddenly felt numb, buzzing silence filling his oversensitive ears. The vampire that turned him had gotten his personal number somehow. How was that possible? His phone buzzed again as he received another message from his creator, this time with a picture. He let out a gasp seeing the message and then the picture

 _She's next_

"JJ!"

* * *

 **I love cliffhangers!**

 **I know I'm evil but this was in the description. Anyway to all those wondering Cassie/Scar's girlfriend will make an appearance as well as Spencer's boyfriend. Yep I said is I gave our precious nerd baby a boyfriend.**

 **I know this is in the Mortal Instruments category but I'm gonna be going off more of the Shadowhunters characterizations or a mix of both as I've read most of the books and am all caught up on the show.**

 **The TMI gang will be appearing in future chapters. And for all those Malec fans, don't worry I got you covered and I'll most likely put Saphael in this too.**

 **If it's not obvious already I love gay ships.**


	3. Kidnapping

**Okay next chapter. I am mixing up a bit of lore to create my own just a fair warning for that.**

 **We learn a bit more about Cas/Scar and Spencer's past in this chapter as the team his planning JJ's rescue missing.**

 **Enjoy the chapter, I believe this is the longest one so far.**

* * *

JJ blinked her eyes open, squinting in the dark trying to make out the room around her. She sat up and discovered her wrists bound in front of her by a thick leather rope, she was in a cage thick iron bars keeping her trapped in the confined space. The sounds of metal hitting metal caught her ear and she looked around her eyes not adjusted to the dim lighting and she saw other captives also in cages with identical leather bonds on their wrists, except all these people were extremely pale and had blood running down their necks from multiple pairs of pin prick holes. She could help but let out a gasp, the unsub that got Morgan had gotten away and now he had her. She crawled over to the side of the cage and picked up a small piece of rotted wood, tossing it to the cage beside her to get the other persons attention. The other captive, a young brunette girl who was almost as white as a sheet started at JJ with curiosity.

"You're new." She spoke her voice raspy and strained, JJ was able to tell easily that she was dehydrated, this man didn't care about the health of his captives he just wanted their blood.

"I am." She spoke gently, "What's your name?"

"What should I tell you, you could be one of his and then attack me for giving up the secret."

"I'm not I promise. Here look" JJ struggled for a while trying to fish in her pockets to see if her had taken her badge or not. She remembered being knocked out on her way home from work so she should still have it on here. She grinned as she pulled out the leather wallet containing her federal ID. She held it up for the girl to see.

"You're FBI?" She asked her eyes widening.

"I am, and my team is work on this very case, they're coming for us.

"Really?" She asked hope lighting up in her dull eyes.

"Yes" She assured, "Now, can you please tell me your name."

"My name is Rebecca. Rebecca Lewis."

* * *

Morgan paced the meeting room overlooking the BAU bullpen waiting for the rest of the team to arrive after he called Hotch and had him call everyone in. He told Hotch about JJ but Hotch hadn't told the team only that they had a case and they were needed right away. Besides Hotch who was there when Morgan arrived thanking that it was still dark out so he could travel, Garcia showed up next her hair a bit of a mess and wearing a light dusting of make up, looking a bit tired but ready to work. Rossi then showed up his hair pulled into it's usual style but his clothes a bit wrinkled and ruffled showing his hurry to get into work. Reid and Cassie were the last to show up, Reid looking exhausted and Cassie wide awake.

"How are you so chipper?" Reid asked glaring at her, the black eye she had given him yesterday for the ice incident shinning a bright purple.

"Insomnia may be a bitch but it's helping out in this case." She grinned. "I don't even need a coffee."

"Good I can have yours" He grumbled.

"Okay" Hotch stood up. "I'm sorry for having to call you all in thi-"

"Shouldn't we wait for JJ?" Garcia piped up her feather topped pen waiting to take notes on her pink glittered covered notebook as she voiced her concern about one of their team members not being there.

"That's actually part of the case." Morgan piped up. "A few hours ago I received a text from Dunkan Raven, the man that kidnapped me, and that's responsible for all the bodies being drained of blood being dumped in New York City. He's taken JJ." He held up his phone to show the picture he received. of JJ unconscious with a nasty cut on her forehead mostly caused by whatever was used to knock her out.

"Thought you'd hear the last of your creator. You thought wrong little fledgling, Im going to make as many as I can, and no one can stop me." Rossi read out the first text from Duncan. "Fledgling?" He questioned turning to Morgan for explanation who sighed.

"I didn't include it in my first report because I had trouble remembering things from the concussion but I remember now that he's deluded himself into believe he's a vampire and he believes he;s going to make an army of them to overthrow human kind. I know he's brainwashed some young kids and druggies believe his delusion and they're the cause of the bodies, they drain other victims of their blood over time and when there's none left the dump them and if you're asking I honestly have no idea if he's gonna try and brainwash JJ or use her as 'food'" he name air quotes around the word food causing Garcia to shiver and fear for her closest friend.

"I've already called the New York precinct. Wheels up in a half hour. Go home, grab you bags and meet at the tarmac then. We have to work this case without it getting personal or else we're being pulled from it. I understand that JJ's one of us and we're going to find her but we need to make sure to work this case with a level head." Hotch told the team.

"Morgan" Cassie jogged up to him, "Let me drive you to your place and they we can win by Spence's and mine apartment, you shouldn't be driving with such little sleep.

"I already have a bag but I wouldn't mind a ride, thanks Cas" He smiled at his friend.

"No problem" She smiled swinging her keys around her finger and headed toward the elevator.

"Pray that you arrive with you life intact." Spencer whispered to Morgan as he walked past. "Her driving is worse than yours."

"I heard that. You want another black eye?"

"You're an idiot Cas."

"But I'm you're idiot." She smiled innocently at him as the elevator dinged and the doors opened Cas, Spencer, and Morgan stepping onto it.

"I need a better idiot." He muttered to himself and Cassie smacked him upside the head having hear the comment. Morgan sighed at the two interacting like children.

After a terrifying 5 minute drive to Reid and Cassie's apartment Morgan was finally able to unclench his hands from the seat. "You're right." He looked at Reid. "She's terrifying."

"Well we're here aren't we." Cassie rolled her eyes and walked towards the buildings entrance. The three climbed the stairs to the apartment. As Reid was unlocking the door just as a woman with fiery red hair approached the trio. The three looked up and Derek could tell by her scent she was part of the undead.

"Who are you?" He growled.

"We've already talked agent Morgan" The woman smiled, her thick Russian sounding familiar.

"Anastasia?" He asked confused, turing to look back and Spencer and Cassie who looked confused. "What're you doing here mom?"

"She's your mom?" He asked.

"Yup" She replied.

"So…you wanna come in?" Spencer asked.

"Of course, thank you Spencer, and yes Scarlett can you blame a mother for visiting her child after not seeing her in person for many years." Anastasia replied with a warm smile

"I thought it was only a few months." Cas/Scarlett trailed off in thought as Spencer rolled his eyes at her.

"So, how long have you been a vampire?" Spencer asked Morgan as the four entered the apartment.

"Huh? How'd you know?" Megan asked him staring his friend down terrified that his friend would look at him like a monster, something inhuman that couldn't be controlled. Spencer was a man of science how could he even believe in things like vampires.

"I'll let you know later, just tell."

"It happened when the unsub kidnapped me last month." Morgan mumbled.

"KNEW IT!" Scarlett cheered as Spencer swore at the same time.

"Scarlett!" Anastasia scolded and she shut up immediately at that. Morgan gave the two a confused look. Spencer snorted at the scolding smiling at Cassie or Scarlett the two names were confusing him. She sighed and turned to Morgan.

"My real name is Scarlett Nightcrest, she's my mom as I said outside" She pointed to Anastasia.

"So you're a vampire too?"

"Half vampire yes, dad's a shadowhunter, his blood is a little more dominate than the demon infected blood, same with my siblings, I can eat and drink regular food and drinks, but I also need blood to survive." She smiled gently showing off her fangs.

"What's a shadowhunter?" Morgan asked slowly. Spencer turned to Anastasia.

"Have you not told him yet?" He asked slowly

"Haven't had the time too, just contacted him yesterday." She smiled gently sitting on one of the couches.

"We'd lost to stay mom but we're on a case, we need to pack some things and then head out." Scarlett said apologetically.  
"That's alright my dear, where are you headed too?"

"New York." She smiled knowing her mom would be there in a days time.

"We'll have time to catch up then." She smiled at her daughter and gave her a hug. She turned to Spencer, "Take care of her."

"I always do." He replied.

"I'm not a child I can look out or myself." Scarlett said throwing her go bag on the couch and walking over to the fridge to get some bottles of blood, shoving the small flask into her jacket pocket. She turned to look at Morgan who was staring at the scene in complete and utter shock. "We'll explain on the ride to the airport." She assured him with a fanged smile. "We have to go but I'll see you later mom" She gave Anastasia one last hug and then the three agents headed out to the underground garage of the building.

"So, story?" Morgan asked as the there were heading to the airport

"Story" Scarlett smiled "So listen up, it starts millennia ago, demons have been around since the beginning of documented times, when the mundanes were created demons began to mingle with then in disguise, masked as humans, they mated and then warlocks were born, there were few in the beginning but that's how the humans knew of demonic magic and activities. There was also the fey comprised of pixies, unicorns, brownies, and the seelies society but they kept quiet, in their own culture of solitude, the first generation was created through angels and demons, most are just offspring of the original fairies now. As the demons continued to wreak havoc on the earth, the angel Raziel decided that the earth need warriors of great strength to help fight back the demons. He then gifted an ordinary man by the name of Johnathan Shadowhunter with 3 magical items, the Mortal Cup, Mortal Sword and the Mortal Mirror. He mixed his own blood with Johnathan's in the cup and told Johnathan to drink it, he did thus becoming the first nephilim or shadowhunter, angel Raziel then left with the responsibility of creating more shadowhunters to help fight off the demons. Time went on and more and more shadowhunters were created, they started families and came up with new "shadowhunter" names, so they could recognize if the other was a warrior with the Angel Raziel. During this time the vampires and werewolves were created, demons infected blood and viruses started to infect and turn mundanes into either bloodthirsty creatures who couldn't be in the sunlight or anything that they religiously believed in before their turning, and then people with animal-like instincts going through at first painful shifts into a wolf at the full moon of each month. After most of the demons were sent back to hell the shadowhunters saw that the mundane world needed protection from the dangers of vampires, werewolves, warlocks, and the Fair Folk. The first of many accords were created. The laws for both shadowhunters and the downworlders, what shadowhunters call vampires, werewolves, warlocks, and the Fair Folk as a group. At this time shadowhunters believed that their angel blood made them superior to all the downworlders, because each one had a demonic trait to them. The discriminated against the downworlders and hunted them down for the littlest mistake." Scarlett took a deep breath as she finished the story. "Also anyone that's not mundane is part of the shadow world, it's masked by the glamour that's why normal people, or mundanes can't see that people are really vampires, or that person has really weird tattoos, nope, shadowhunter." She pulled up her sleeve to reveal some runes. Showing them to Morgan who was in the back seat. "They give shadowhunters enhanced abilities like sight, hearing, agility, and speed. But that's basically all you need to know about our little world." She smiled gently at Morgan who still looked confused."I know you didn't enter willingly but, welcome."

"Okay but what about Reid. How do you fit into this? And how can you be both vampire and Shadowhunter?" Morgan asked.

"I'm a warlock shadowhunter hybrid, similar to Scar." Reid replied. "I can tell the hybrid stories. I'm just around 267 years old, born to a shadowhunter mom and warlock dad. Shadowhunter blood is dominate compared to any other blood so I am a shadowhunter and I trained to be one that's why I can have runes on my skin, if a normal mundanes is runed they'll either die or gone insane and become what we call a forsaken, which we have to kill because that's a monster with no control. It was tough for me to hide my warlock mark. Sorry" He apologized seeing Morgan's confused face at the mention of warlock marks. "All warlocks have a supernatural mark that shows they're not human, say wings, horns, tail, different skin colour or eyes. I personally have wings which I keep hidden with a glamour, I hid them throughout my training as a shadowhunter and when I went home at night my dad taught me how to control my magic. It was hard when mom died because of a demon and then my dad by the very same demon because he wanted to exact revenge for my mother. I was finished my shadowhunter training but my magic schooling was still incomplete and I was struggling with control considering my father was a very powerful warlock I had strong natural magical abilities. A warlock, Magnus Bane took me in, this was in England at the time, he sorta adopted me as a younger brother and taught me all I need to know. We parted ways when I grew up and wanted to go back to the shadowhunters. I am immortal because of my warlock blood I had to keep moving around because of this. I didn't want my fellow shadowhunters to discover I was more than what I said I was. I travelled from country to country, institute to institute as I grew older and then I happened upon the Toronto institute, which was headed by a male shadowhunter. Who was married to a vampire. Anastasia and her husband, Richard Nightcrest invited me to stay at the institute because they knew of my parentage after I told them knowing they would understand." He smiled over at Scarlett and she rolled her eyes guessing he was going to tell embarrassing stories of her when she was little.

"I'm older that Scarlett, she isn't even 100 yet" He snickered as Scarlett slapped him upside the head and pouted. He calmed down and continued.

"After a few months of me staying there, Anastasia announced she was pregnant and Richard was obviously excited, children of his own to take up the Toronto institute mantle. Scarlett and her twin brother Alexander were born 9 months later, perfect mix of shadowhunter and vampire blood in them. Scarlett had just a little bit more vampire in her and Alexander, we call him Ace, had just a little bit more shadowhunter in him. I help Richard and Anastasia raise the 2 and trained them in the art of shadow hunting while their mother taught them to control their urges. After Scar over here almost ate the family cat." He laughed.

"One time!" She glared at Spencer.

"To answer any further questions about how Richard is still alive today after these many years, well it's because of the very, very rare vampire mark. We shadowhunters have marks, but other downworlders have marks as well. Vampires, werewolves, Fair Folk, warlocks have a lot too. The vampire mark is giving through the bite of a vampire during intimacy. The 2 must love each other unconditionally. When the pin prick wounds left by the fangs heal it leaves 2 stars where the fangs punctured the skin. Gifting the receiver with immortality if they do not already possess it. By the way not many nephilim know that hybrids really exist so we'd appreciate it if you kept this to yourself." Spencer smiled.

"Will do, magic man." Morgan smiled at his best friend.

"You're taking this well." Scarlett observed leaning forward to examine Morgan with her eyes.

"Well, I guess I have to accept it. I'm part of this world now." He shrugged

"Oh, that reminds me, you're not a daylight yet." Scarlett said fishing the flask from her jacket. "Have a small skip of that." She passed it back to Morgan "It's angel blood it will let you walk in the sunlight, but you'll keep all other weaknesses a vampire normally has." She said

"How do you have angel blood?" Morgan questioned her.

"I have my ways" She smirked at him in the rearview mirror.

"Well it looks like you'll have to teach me a few new things." Morgan smiled.

"That we do, but for now, let's find JJ before she's drained or turned." Reid said and the other 2 nodded in agreement as Scarlett pulled up to the airport.

"He look we're alive" Reid remarked sarcastically.

"Shut up you're immortal you survived the black plague you can survive my driving." Scarlett glared at him and got out of the car.

"Hey Cas er-Scarlett, why'd you change your name before going the FBI?" Morgan asked walking with her.

"Are you kidding me?" She laughed. "Who would take an agent seriously with the last name of Nightcrest." She and Morgan laughed as they and Reid approached the plane.

* * *

 **I hope you guys liked it. I sure enjoyed writing it.**

 **Our Shadowhunters gang should be appearing next chapter along with a very panicked Simon about his big sister.**

 **Review Please.**


	4. Destination: New York

**Okay. Here's the next chapter. I'm keeping Simon as a vampire, because I like him as a vampire.  
**

 **I'm finally bringing in the TMI characters, keeping Vargas alive because I really like her character and wish she wasn't killed off as early as she was.**

 **Anyway, here's chapter four of Changing Blood.**

 **Destination: New York.**

* * *

Magnus Bane groaned as his phone started ringing again, he had already declined the caller twice in favour of taking a cat nap with his boyfriend.

"Just answer it" Alec advised his, "It's obviously important."

"Fine." The warlock grumbled, rolling his eyes and detaching himself from Alec before answer the phone. "This better be good whoever you are."

"Long time no see eh Magnus?" Spencer's voice came through the phone.

"Spencer? Where the hell have you been, it's been at least 50 years since we've talked, and why do you sound Canadian."

"Spend almost a century living in Canada and see what it does to you" The younger warlock remarked.

"Not that it's not great to hear from you but why are you calling? You okay?" Magnus asked, he may not like having his cuddle time with Alec being interrupted but Spencer was family to him.

"I'm fine but the FBI team I'm now working with is flying down to New York to work on the recent murder cases in Brooklyn and the surrounding areas, the vamp ones. Surprised the clave hasn't tried to cover it up yet, but anyway just giving you a heads up. Scar's with me as well as a freshly turned vamp but she's keeping him controlled." Spencer told his long time friend.

"Okay thank you for the information, Can I go now?" Magnus was starting to get irritated, he had left the heater on and his apartment was starting to get warm, prompting Alec to remove his shirt and he couldn't help but stare at his boyfriend's amazingly sculpted body, resembling a greek god and the way his runes ran along his curves, it was making Magnus' imagination stir with dirty thoughts of what he could do to Alec.

"Why?" Spencer's voice cut off his nasty thoughts. "You have a girl or guy to get back to."

"Yes in fact I do, and before you ask yes I am answering this phone call while descent, we were just cuddling and watching a movie."

That's what you always say Mag." Magnus could swear he heard the eye roll from over the phone line.

"Like you and Nathen." He remarked and Spencer fell silent. "Touché. Anyway, text you when we land. Later Magnus."

"Later Spencer." With that the two hung up, Magnus smiled finally hearing from Spencer after quite some time, having missed the younger brother he once saw as a little brother now still a little brother but also a best friend.

"Who was that?" Alec asked as Magnus hung up and put his phone down,

"Old friend that I haven't had contact with in about 50 years, no idea how he got my number. He somehow got a job with the FBI and he just warned me that they're coming to investigate the vamp murders that have been going on around town." Magnus shrugged wrapping her arms around Alec again as the blue eye shadowhunter leaned into the warlocks arms.

"I'll get his number from you later, so we can figure out a way to get some shadowhunters into those crime scenes."

"Isn't Luke working on that one too?" Magnus questioned

"Yeah but Luke's been working with the NYPD for year, look suspicious if he was just suddenly bring in new people, less suspicious with the FBI." Alec smirked

"They way you strategize is just so sexy." Magnus bit his lip and stared down Alec's chest before his amber golden cat eyes met Alec's sky blue one, both men were leaning in for a passionate kiss as Alec's phone went off.

"By the angel!" Alec yell. "I can't have one night off with my boyfriend." He angrily grabbed his phone and accepted the cal not looking at the contact info.

"Alec!" It was Simon and he sounded out of breath, how could a vampire sound out of breath?

"Simon? What is it? Anyone hurt? Is it demons?" Alec immediately started interrogating the young vampire down the phone like.

"Go-" Simon coughed and then returned to speaking. "No, but my sisters missing and I think it's that vampire that's been killing mundanes. At least, it smells like something undead has been in my house."

"Call the others I'll be right there." Alec sighed pinching the bridge of his nose, he hated to cut his day with Magnus short but if it was Izzy who went missing he'd want all the help he could get to find her. He ended the call and turned to Magnus.

"Simon's sister has gone missing, he suspects the serial vamp, I'll head over to his place to check things out. He's probably already called Luke who's filed the report so no doubt the FBI will be there making it easy for me to talk with your friend. What's his name?"

"Spencer Reid, and I'll come too, a little warlock tracking may help Steve find his sister." Magnus smiled, loving that he got to work with Alec.

"Not you're just messing his name up on purpose." Alec laughed and he slung his quiver over his shoulder.

"You know me so well my angel." Magnus laughed as he summoned a portal and the two stepped through it heading to Simon's.

* * *

There were aspects of being a detective that Luke both loved and hated. Today he was living all the scenarios he hated. A serial killer at large in his city that he could easily stop but that was most likely start a true war between his pack and the rest of the New York vampires, besides Simon who he had just gotten off the phone with. He sighed as he approached the captain's office. He knocked and opened the door once he got the come in. "Captain Vargas. We have another kidnapping." He sighed again as she looked pissed.

"Who now?" She questioned.

"Rebecca Lewis. Her brother just called, he's Clary's best friend so he called right away when he noticed she wasn't home, he knows her routine and I agree with him that this isn't her behaviour, she's in trouble and the serial killer's type, young and fit."

"I believe you Garroway, good this I already called the FBI in, start a file on her and get some officers over to the Lewis house, I'm sure some of the BAU will join you shortly after they touch down here.

"Will do captain." Luke nodded before exiting the room, wondering how in the hell the FBI was going to be able to capture a vampire on a rampage and why the hell the clave hadn't done anything about him yet. His supernatural hearing picked up the main door to the precinct. The FBI BAU team he , he stood up and made his way to great them.

"Agents." He greeted the 3 agents walking up to them. A stoic looking one with a hard face and dark hair, one with a loose fitting high quality made jacket, and a female dressed smartly with dark shoulder length hair.

"Detective" The stoic looking one nodded to him.

"Garroway" He held out his hand.

"Hotchner, and Agents Rossi and Prentiss." He referred to the two standing next to him. "I've already sent other agents to the most recent crime scene and the coroner."

"Redirect the one's heading to the corner, we just got another report of a missing person. Rebecca Lewis, 20. She's the older sister of my step-daughter's best friend. I hope that's not a problem as I intend to work this case as level headed as I can."

"No worries, one of our own agents has been taken as well so we're in the same boat as you." Agent Rossi informed him.

"Very well." Luke nodded now fearing he'd eventually have to tell them about the shadow world. Rebecca knew of it because of Simon but he hadn't gotten the chance to tell her everything about it yet, she just knew that he was a vampire and that other creatures existed, some were good, some were bad. "Follow me, we have a room set up and you can meet the captain." Agent Hotchner nodded as Luke lead the 3 agents into the heart to the precinct. Luke lead the 3 to a secluded meeting room with 3 boards already set up with victims names next to crime scene photos, a partial geography map set up with last know sightings, places of residence, and where they were found. All the victims that were dumped were usually in alleys by dumpsters and the ones that hadn't shown up yet, Luke suspected that the vampire responsible for all this was turing them for his own personal army. Probably to fight against the shadowhunters, mundanes, and the rest of the downworlders.

"This is all we have." He sighed, "There's still some files that I'm looking over at my desk but I'll bring them here and set one up for Rebecca and your missing agent."

"Jennifer Jareau." Prentiss spoke up. Luke nodded, I'll get those started, if you need anything, my desk is the closest to the stair case in the bullpen. I'm sure Captain Vargas will be here to greet you as soon as she can."

"Which is now." The captain said walking up the agents. "I sure hope that the FBI sent us more than 3 agents." She remarked seeing the 3.

"There's 8 of us in the unit, others are already at victims homes or dump scenes." Hotch informed her. "I'm SSA Hotchner, these are SSA Rossi, and SSA Prentiss." He introduced Rossi and Emily.

"Thank you so much for coming down here, I understand you've dealt with this killer before." Vargas shook their hands as introductions went around.

"We have, he kidnapped one of out team members and held him hostage for about 90 hours. We managed to find him in an abandoned warehouse, the unsub had fled. No idea why." Hotch said.

Luke frowned, if the vampire had left their teammate alive, he was most likely _not alive_ he was probably turned, he'd have to meet him and get a whiff of his scent, but he'd have to keep a close eye on that one, this vampire was an older one. With strong Encanto skills. Could manipulate the strongest of minds.

"Luke? You okay?" The captain pulled him from his thoughts.

"After hearing that, I'm just worried for Rebecca." He told a half truth, he was beyond worried for Simon's sister, but also that if he could trust one of the FBI agents.

"We'll find her." Hotch reassured the detective, "Along with agent Jareau and all the other victims." The agent said confidently and Luke could've sworn he saw a small smile come from the agent.

"We will." He repeated confidentially.

* * *

Scarlett sat in the passenger seat pouting as Morgan drove her and Reid who was sitting in the back reading over files to the Lewis family house, which they had been rerouted too after getting a text from Hotch.

"Suck it up Scar, Morgan called driving since you drive like a maniac." Reid rolled his eyes at his friend.

"So what if I first got my license in 1946." She grumbled slouching into the leather seat of the SUV.

"And you haven't renewed it?" Morgan questioned her.

"Piece of advice, Encanto your examiner. Makes it so much easier." She grinned.

"What's Encanto?" Morgan asked.

"Vampire mind control, you're able to influence their actions and choices, like making a mundane consent for you to bite them or in Scar's case, to pass a driving test."

"To each their own." Scarlett shrugged giving Morgan a fanged grin. "It's a skill you learn over time, you don't ever have to use it if you don't want to, but I've used it to talk myself out of a lot of tickets and, at least when I was young, being arrested for being in a relationship with another woman. As a bisexual woman, it's great to see how far lgbt rights have come. She smiled fondly thinking of her wife.

"So does your girlfriend know you're a vampire, would I ever be able to tell the person I end up with what I am." Morgan asked.

"You will." Reid leaned forward and put a hand on his friends should reassuringly. "There's no rule against it, in fact it's encouraged, better than her being shocked by it and going to the media." Reid said.

"Who said they'll be a she?" Morgan smirked at Reid through the rearview mirror.

"Your gaydar needs tuning Feathers, how could you not tell he's bi as shit. He literally checks out as many men as Magnus does, maybe even more."

"Defiantly more, now that Magnus has a boyfriend." Reid replied back.

"Wow, someone to mend his hear after Camille, didn't think that would happen this quickly." She remarked.

"Why'd you call Reid feathers?" Morgan asked Scar interrupting her and Reid's conversation.

"His wings, he calls me fangs." She explained and Reid resumed the conversation with her.

"Well it has been almost 150 years since Camille, and he was full on head over heels in love with her. She crush him, completely destroy every positive emotion he had towards love."

"Magnus is the one who took you in right Pretty Boy?" Morgan asked.

"Yeah." Reid nodded, "He's like an older brother, he's the High Warlock of Brooklyn so both of us will probably be paying him a visit during this trip."

"High Warlock?" Morgan asked looking for an explanation.

"Most powerful in a given area, I'm technically the High Warlock of Toronto." Spencer shrugged, "It's really just a formality for me. Friend of mine Casandra is handling all the High Warlock duties back home. I still have the title because I am older and more powerful than her."

"You really are that powerful?" Morgan asked and Reid nodded.

"Even with diluted warlock blood I accidentally summoned a demon at the ripe age of 9, weak demon, mom killed it in an instant because it was coming after me but yeah. 9 years old and already conjuring portals to hell. That's when dad started training me in advanced magic." He smiled lightly reliving the memory of his family.

"You miss them?" Morgan asked gently.

"All the time, but mom died protecting a mundane family and dad, though it may have started out as revenge for my mother, ended up saving an entire mundane village in the process. They both died heroes, and as I do wish they could've lived longer, the life of a shadowhunter is generally a short one, and my dad was a real hot head, protecting my mother from anything and had a temper about it." He sighed

Scar reached back and took her friends hand, squeezing it in reassurance. Reid squeezed back and offered a small smile.

"So Camille?" Morgan asked trying to change the topic as he slowed when they entered a high traffic area.

"Vampire Magnus was dating in the 1830s. Completely in love with her, but she was narcissistic, and generally a horrible person, didn't believe immortals could love one another. He hasn't cared about someone that way since. He has a boyfriend now and he's starting to act like he used to back then."

"Girlfriend, then boyfriend?" Morgan questioned.

"He's bisexual, attracting to males and females, just like me" Scarlett grinned.

"And I'm pansexual, any gender, anyone." Spencer grinned.

"Wow, for 2 people who are 100 years old-"

"Not Scar." Reid interrupted earring a glare from the vampire.

"For 2 people who have been alive and lived through most of the time periods where being lgbt was criminalized. When did you know? How did you know?"

"Magnus" The two spoke at the same time.

"He's fabulous." Reid giggled lightly remember his friends eccentric style of clothing, make-up, accessories, and hair styling. Morgan laughed alone with his friends and coworkers.

"And history is much gayer than you think. Historians have just made it straighter because of heteronormativity." Scarlett rolled her eyes.

"And on that lovely note, We're finally here." Morgan said pulling into the Lewis' driveway.

"Let's catch us a serial vamp." Scarlett said unbuckling herself and opening the door. The three agents walked up to the door, as Morgan raised his hand to knock Scarlett grabbed his hand.

"Morgan no!" She nearly screamed, pulling him away from the door. "Don't touch the door." She warned him.

"What why?" He asked as Morgan stepped in front of them butting a barrier between the two and the door.

"It's marked with the Star of David." Scarlett explained, "Vampires that don't necessarily follow a religion are vulnerable to all religious symbols." She explained, that means both you and myself, Reid's the only one who won't be burned by touching the door. Reid knocked and waiting for an answer, a petit women answered.

"Yes?" She asked.

"Elaine Lewis?" Spencer asked politely.

"Yes. What can I do for you?"

"My name is Dr. Spencer Reid, I'm with the FBI." He held up his badge, "I'm here with my colleagues SSA Derek Morgan, and SSA Cassandra Barnes." He motioned to Morgan and Scarlett, mentioning her fake identity she came up with. "We're hear about Rebecca's disappearance. May we come in?"

"No need, I can tell you who took my daughter and who's been killing all those people." She said her voice suddenly becoming harsh and filled with venom.

"His name is Simon Lewis. He used to be my son." She spoke and the 3 agents shared a nervous look. A voice spoke that made all 4 heads turned towards the source.

"Mom?"

 **I love cliffhangers so get used to them.**

 **I want to thank all the readers that have read up to this point. I know this is the only story in this category of crossovers and my over imaginative mind has just come up with this shit show of a story.**

 **Saphael is a go for this I've made up my mind  
Scarlett's wife will take a while to appear because I am still figuring out her character. (She doesn't even have a name ****yet)  
And I've now decided that this will turn into an eventual Moreid fic. Sorry not sorry**

 **My gay ass will turn this entire story into a gay paring story probably.**


End file.
